This invention relates generally to fasteners for fastening objects to metal channel framing and, more particularly, to a nut having means thereon for clamping the nut to the channel prior to and during securement of the object to the channel.
Electrical conduit, pipes, fixtures, etc. are commonly supported overhead or vertically by channel framing conventionally having side flanges with inwardly turned, hook-shaped lips defining a slot therebetween. Typically, an elongate nut (narrower but longer than the width of the slot) is used for securing objects to the channel, the nut first being aligned with, entered into and passed through the slot, and then turned 90.degree. to a crosswise position with the outside face of the nut engaging the inside faces of the channel lips. Various means have heretofore been used for holding the nut against the channel in its crosswise position prior to and during securement of an object to the channel.
One such means is a coil compression spring on the inside face of the nut. Upon insertion of the nut in the slot in the channel, this spring reacts against the channel bottom and pushes the nut against the channel lips. This arrangement has several serious disadvantages, however, one being that each channel of different depth requires a spring of correspondingly different length, thus greatly increasing the number of fastener sizes which have to be stocked. Moreover, while securing objects to the framing, the nuts tend to tilt and topple over into the channel. It is also difficult to use the channel as a raceway for conduit, wires or the like since the spring substantially blocks the entire channel.
Another prior art means for holding the nut against the channel is a coil spring attached to the outside face of the nut for spanning the slot in the channel and pulling the nut into engagement with the channel lips. This means also has its drawbacks, however, inasmuch as the spring tends to slip off the lips of the channel and the nut to fall into the channel.
Yet another prior art means is a cradle for the nut having spring fingers or lugs extending outwardly from the outside face of the nut at opposite ends thereof. The lugs are engageable with the outside faces of the channel lips to pull the nut into engagement with the inside faces of the channel lips upon turning the nut to its crosswise position. The cradle, however, lacks means extending beyond the sides of the nut to prevent it from falling into the channel upon insertion of the nut into the slot in the channel.
The fasteners disclosed in my U.S. Pat. No. 4,146,074, issued Mar. 27, 1979, and my co-pending U.S. patent application Ser. No. 76,461, filed Sept. 17, 1979, now U.S. Pat. No. 4,285,379, solve the aforementioned problems in that they provide a clear channel for carrying conductors and remain securely in place on the channel prior to and during securement of an object to the channel. However, while the installation and use of these fasteners have been entirely satisfactory, their manufacture is relatively costly. For example, in the manufacture of the fastener disclosed in my U.S. Pat. No. 4,146,074 a separate machining step is required to cut slots in the sides of the nut, and in the manufacture of the fastener disclosed in my co-pending U.S. patent application Ser. No. 76,461, a clamp member and a separate retainer member must be stamped from blanks of sheet metal and then assembled with the nut to form the fastener.
Reference may be made to U.S. Pat. Nos. 1,306,100 and 3,483,910, and British Pat. Nos. 513,368 and 1,061,149, all of which disclose fasteners of the same general type as that of the fastener of this invention.